1. Field of the Invention
This invention is related to a structure of an electronic thermometer, and in particular to one which overcomes the insufficiency of the prior art and enables the pushbutton switch to be operated longitudinally thereby making it easier to be used in the mouth or similar situation and therefore meeting the needs in certain special occasions. Furthermore, the structure of the electronic thermometer is easy to manufacture, low in cost and reliable in use.
2. Description of the Prior Art
The conventional mercury-in-glass thermometer is a thermometer consisting of mercury in a glass tube. Calibrated marks on the tube allow the temperature to be read by the length of the mercury within the tube, which varies according to the temperature—adoption of the characteristics of the mercury, where the mercury volume will expand when hot and contract when cold. As the conventional mercury-in-glass thermometer is made by glasses, cautions shall be taken when use to avoid breaking it, especially when applied to mouth or anus, where the leakage of the mercury is harmful for human body. Furthermore, for those patients required constant body temperature monitored, the conventional mercury-in-glass thermometer lacks the comforts and conveniences of taking one's temperature at anytime. Thus, an improved thermometer shall be investigated to combat the inefficiencies of the conventional mercury-in-glass thermometer.
Electronic thermometers have been developed recently to take one's temperature; however, they come with little waterproofing capability. The horizontal design of the switch button for the electronic thermometer made it inconvenient under certain specific environments and when applied to mouth. Japanese Patent Application Publication No. 61-191928 discloses a structure of switch button for electronic thermometers, comprising a sealed member inside the cover located at the end of the electronic thermometer, a flexible piece made of soft resin compound is liquid sealed at the top of the sealed member, an adjustable switch button is equipped at the top of the flexible piece and the press button is located in the switch hole at the middle of the said cover, with the top bulged out of the switch hole and a base connecting the flexible chip, and an “O” shaped circular seal between the surface of the press button and the switch hole. An of/off switch device is provided at the bottom of the flexible piece and includes a plastic base, and a switching spring plate fixedly mounted on the top of the plastic base. The top of the switching spring plate is always in contact with the bottom surface of the flexible piece. Further, the plastic base is provided with a contact plate corresponding to the switching spring plate, and the switching spring plate and the contact plate are respectively connected to the anode and cathode of the electrical circuit. When the switch button is under external force, the switch button moves down, providing downward pressure on the flexible piece to deform it flexibly. The flexible piece in turn forces the switching spring plate to deform until the end of the switching spring plate touches the corresponding contact plate to switch on the electrical circuit, and starts the electronic thermometer.
Although the above-mentioned structure allows switch button at the bottom of the electronic thermometer to be manipulated vertically, the adoption of metal spring plate with the on/off switch device comes with the following disadvantages: 1) as the on/off device comprises of a plastic base and metal spring plate, it cannot be manufactured in one time; further processes to bend the spring plate and to adhere the plastic base are also required. This complex structure and assembly provide higher chances of producing defective products; 2) there's quite a large discrepancy in the structure of the presently used electric thermometers, which associates with higher improvement costs and less business satisfactory; 3) the spring plate may become inelastic after numerous bending deformations to result in the failure of the switch button, thus providing less reliability. In conclusion, there are still insufficiencies for the current skill of art, and room awaits further improvements.